| /* | |
| * SoftDog: A Software Watchdog Device | |
| * | |
| * (c) Copyright 1996 Alan Cox <[email protected]>, | |
| * All Rights Reserved. | |
| * | |
| * This program is free software; you can redistribute it and/or | |
| * modify it under the terms of the GNU General Public License | |
| * as published by the Free Software Foundation; either version | |
| * 2 of the License, or (at your option) any later version. | |
| * | |
| * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide | |
| * warranty for any of this software. This material is provided | |
| * "AS-IS" and at no charge. | |
| * | |
| * (c) Copyright 1995 Alan Cox <[email protected]> | |
| * | |
| * Software only watchdog driver. Unlike its big brother the WDT501P | |
| * driver this won't always recover a failed machine. | |
| * | |
| * 03/96: Angelo Haritsis <[email protected]> : | |
| * Modularised. | |
| * Added soft_margin; use upon insmod to change the timer delay. | |
| * NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate | |
| * minors. | |
| * | |
| * 19980911 Alan Cox | |
| * Made SMP safe for 2.3.x | |
| * | |
| * 20011127 Joel Becker ([email protected]> | |
| * Added soft_noboot; Allows testing the softdog trigger without | |
| * requiring a recompile. | |
| * Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT. | |
| * | |
| * 20020530 Joel Becker <[email protected]> | |
| * Added Matt Domsch's nowayout module option. | |
| */ | |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
| #include <linux/module.h> | |
| #include <linux/moduleparam.h> | |
| #include <linux/types.h> | |
| #include <linux/timer.h> | |
| #include <linux/watchdog.h> | |
| #include <linux/notifier.h> | |
| #include <linux/reboot.h> | |
| #include <linux/init.h> | |
| #include <linux/jiffies.h> | |
| #include <linux/kernel.h> | |
| #define TIMER_MARGIN 60 /* Default is 60 seconds */ | |
| static unsigned int soft_margin = TIMER_MARGIN; /* in seconds */ | |
| module_param(soft_margin, uint, 0); | |
| MODULE_PARM_DESC(soft_margin, | |
| "Watchdog soft_margin in seconds. (0 < soft_margin < 65536, default=" | |
| __MODULE_STRING(TIMER_MARGIN) ")"); | |
| static bool nowayout = WATCHDOG_NOWAYOUT; | |
| module_param(nowayout, bool, 0); | |
| MODULE_PARM_DESC(nowayout, | |
| "Watchdog cannot be stopped once started (default=" | |
| __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
| static int soft_noboot; | |
| module_param(soft_noboot, int, 0); | |
| MODULE_PARM_DESC(soft_noboot, | |
| "Softdog action, set to 1 to ignore reboots, 0 to reboot (default=0)"); | |
| static int soft_panic; | |
| module_param(soft_panic, int, 0); | |
| MODULE_PARM_DESC(soft_panic, | |
| "Softdog action, set to 1 to panic, 0 to reboot (default=0)"); | |
| /* | |
| * Our timer | |
| */ | |
| static void watchdog_fire(unsigned long); | |
| static struct timer_list watchdog_ticktock = | |
| TIMER_INITIALIZER(watchdog_fire, 0, 0); | |
| /* | |
| * If the timer expires.. | |
| */ | |
| static void watchdog_fire(unsigned long data) | |
| { | |
| if (soft_noboot) | |
| pr_crit("Triggered - Reboot ignored\n"); | |
| else if (soft_panic) { | |
| pr_crit("Initiating panic\n"); | |
| panic("Software Watchdog Timer expired"); | |
| } else { | |
| pr_crit("Initiating system reboot\n"); | |
| emergency_restart(); | |
| pr_crit("Reboot didn't ?????\n"); | |
| } | |
| } | |
| /* | |
| * Softdog operations | |
| */ | |
| static int softdog_ping(struct watchdog_device *w) | |
| { | |
| mod_timer(&watchdog_ticktock, jiffies+(w->timeout*HZ)); | |
| return 0; | |
| } | |
| static int softdog_stop(struct watchdog_device *w) | |
| { | |
| del_timer(&watchdog_ticktock); | |
| return 0; | |
| } | |
| static int softdog_set_timeout(struct watchdog_device *w, unsigned int t) | |
| { | |
| w->timeout = t; | |
| return 0; | |
| } | |
| /* | |
| * Notifier for system down | |
| */ | |
| static int softdog_notify_sys(struct notifier_block *this, unsigned long code, | |
| void *unused) | |
| { | |
| if (code == SYS_DOWN || code == SYS_HALT) | |
| /* Turn the WDT off */ | |
| softdog_stop(NULL); | |
| return NOTIFY_DONE; | |
| } | |
| /* | |
| * Kernel Interfaces | |
| */ | |
| static struct notifier_block softdog_notifier = { | |
| .notifier_call = softdog_notify_sys, | |
| }; | |
| static struct watchdog_info softdog_info = { | |
| .identity = "Software Watchdog", | |
| .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, | |
| }; | |
| static struct watchdog_ops softdog_ops = { | |
| .owner = THIS_MODULE, | |
| .start = softdog_ping, | |
| .stop = softdog_stop, | |
| .set_timeout = softdog_set_timeout, | |
| }; | |
| static struct watchdog_device softdog_dev = { | |
| .info = &softdog_info, | |
| .ops = &softdog_ops, | |
| .min_timeout = 1, | |
| .max_timeout = 0xFFFF | |
| }; | |
| static int __init watchdog_init(void) | |
| { | |
| int ret; | |
| /* Check that the soft_margin value is within it's range; | |
| if not reset to the default */ | |
| if (soft_margin < 1 || soft_margin > 65535) { | |
| pr_info("soft_margin must be 0 < soft_margin < 65536, using %d\n", | |
| TIMER_MARGIN); | |
| return -EINVAL; | |
| } | |
| softdog_dev.timeout = soft_margin; | |
| watchdog_set_nowayout(&softdog_dev, nowayout); | |
| ret = register_reboot_notifier(&softdog_notifier); | |
| if (ret) { | |
| pr_err("cannot register reboot notifier (err=%d)\n", ret); | |
| return ret; | |
| } | |
| ret = watchdog_register_device(&softdog_dev); | |
| if (ret) { | |
| unregister_reboot_notifier(&softdog_notifier); | |
| return ret; | |
| } | |
| pr_info("Software Watchdog Timer: 0.08 initialized. soft_noboot=%d soft_margin=%d sec soft_panic=%d (nowayout=%d)\n", | |
| soft_noboot, soft_margin, soft_panic, nowayout); | |
| return 0; | |
| } | |
| static void __exit watchdog_exit(void) | |
| { | |
| watchdog_unregister_device(&softdog_dev); | |
| unregister_reboot_notifier(&softdog_notifier); | |
| } | |
| module_init(watchdog_init); | |
| module_exit(watchdog_exit); | |
| MODULE_AUTHOR("Alan Cox"); | |
| MODULE_DESCRIPTION("Software Watchdog Device Driver"); | |
| MODULE_LICENSE("GPL"); |